Can we soften the blows of future flood events? Major flood events cause significant and long-lasting disruption to lives. Our research suggests we’re going to experience the impacts of such extreme events more often, as we share increasingly busy spaces with the natural world. But there are some measures we can take to soften those impacts. We should say that not all flooding is bad; it can help shape rivers and floodplains which, historically, has left us with highly prized farmland. But where it is a problem, there are several options. Traditionally, the “go-to” is what some call “hard engineering”. This is where, for example, walls, embankments and engineered structures are built to protect towns and cities from flooding. However, as recent events have shown, these can be vulnerable. Managing runoff in the wider landscape using what’s called “natural flood management”, has a role to play. This is for more persistent, small-to-medium floods by delaying and reducing the peak of the flood. It’s a “nature-based” technique that helps to slow down, store and filter water within river catchments. As well as helping reduce flood events, it also provides wider benefits, such as improving water quality and river-side habitats and should be possible aside productive land uses like farming and forestry. These approaches do mean looking at whole river systems – not just the river but the tributaries and the land around them, so it can mean asking if we can manage the land differently. Scotland has been at the forefront of driving this type of approach and it’s a large focus of our work here at The James Hutton institute. It includes measures to slow runoff and reduce soil loss from fields through river and floodplain restoration, with allied approaches like river woodland. Enhanced options also include soft engineering, such as wood placed in streams to create “leaky barriers” or rock and soil barriers designed to hold water back like temporary mini ponds that work even when soils are saturated. This also helps to create a more biodiverse landscape and can supplement those hard engineering options – so we don’t have to keep building higher walls or treating rivers like pipes with a primary aim of moving water quickly all the way to the sea. Larger flood events mean greater water storage requirements, but this should be possible, distributed appropriately across larger catchments – using new ideas around what’s called ‘adaptive storage’ on floodplains and in channels. Land alongside rivers, streams and ditches and the channel itself needs a natural storage capacity for when it rains and this can be done protecting, or even improving, adjacent farmland from impacts of prolonged wetting and erosion. But managing large floods at large scales is a challenge and we need every trick in the book. Such measures need a lot of land and a lot of it is privately owned. So we need to look at how we do flood risk management on private land, working with those stakeholders, as well as planners and local authorities. There isn’t a single simple answer. Massive storms, as recently seen, could not have been mitigated simply using land management measures and require adaptation of how we live alongside rivers and coasts, as well as reinforcing our respect for nature. For many, new approaches to manage and cope with floods will feel unfamiliar and daunting and may seem complex. We will need education around the solutions, collaboration across the public and private sphere and, importantly, community involvement. December 2023 15 By Professor Marc Stutter
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